Fatigue Saving Throws (3.5e Variant Rule)

From D&D Wiki

The use of psychic skills is fatiguing, but in a different way. Any time using a psychic skill would cause strain the player must instead make a fatigue saving throw for the character. This is a Will save against a DC of 10 plus half the psychic skill’s rank (round up).

A successful save results in no ill effect on the character. A failed save means the character becomes winded: a –1 penalty on both Strength and Dexterity, and an inability to run or charge. The character recovers from being winded after an hour of rest. A winded character who fails a fatigue saving throw become fatigued (–2 to effective Str and Dex, unable to run or charge), requiring 8 hours of rest to recover. A fatigued character becomes exhausted (–6 to Str and Dex, move at half normal speed), requiring an hour of rest, after which the character is fatigued. Finally, an exhausted character who fails a fatigue save becomes unconscious for 10 minutes for each point by which the save failed, and is exhausted upon awakening.

Fatigue saving throws make the use of psychic skills somewhat less predictable, since it’s uncertain whether the character suffers fatigue from using them. Fatigue penalties are also fairly substantial, particularly once they start accumulating. Still, characters with good Will saves (which most psychics have) succeed at their fatigue saving throw more often than not.

Gamemasters looking to make fatigue saving throws more difficult can base them off Fortitude rather than Will saves, meaning they are harder for will-focused characters such as psychics and spellcasters (but easier for character of some other classes). Perhaps some psychic talents—such as Clairsentience and Telepathy—require Will fatigue saves whereas others—such as Psychokinesis and Psychometabolism—call for Fortitude saves.